Commtttator-instjlation-testing device



J. F. CULLIN.

COMMUIATOR INSULATION TESTING DEVICE.

APPLICA T 0 N F ILED JAN. 222222 0.

1,372,945,. Patented Mar 29,1921.

UNITED STATES PATENT OFFICE."

JASPER r. CU'LLIN, or DETROIT,

MICHIGAN, ASSIGNOR TO DETROIT, MICHIGAN.

WILLIAM HARTWIG, OF

Specification of Letters Patent.

Patented Ma1x29, 1921.

v Application filed January 22, 1920. Serial No. 353,348. I

To all 1071,0771 it may concern Be'it known that I, JASPER F. CULLIN, a

citizen of the United States, and residing at Detroit, in the county of WVayne and State of Michigan, have invented a new and Im-. proved Commutator-lnsulatlon-Testing Device, of which'the following is a specification. r

This invention relates to means for determining whether 'or'not the segments'of the commutators of electric dynamos or motors are properly insulated from each other and'from the core, and consists in means for connecting the core-and alternate commutator segments to one end and the other. segments to theother end of a normally open electric circuit including an indicator, so that, should any segment be-short circuited or grounded, this fact may be made known. It consists particularly of a support 'for'the commutator, a contact carrier, a series of spring contacts, one for each commutator segment, two electric circuits, one connecting alternate contacts 1n series andthe other circuit connecting the "remainder of the contacts in series, andran indicator in one of the circuits. It also of segment contacts. 7

In the accompanying drawing, Figure 1 is a plan of this testing mechanism. Figs. 2 and-3 are sections on the line 22 and 3-3 of Fig. 1, respectively. 7

- Similar reference characters refer to like partsthroughout the several views.

' commutator segments are practically un1 versally of copper and mounted on'a steel core and insulated therefrom and from each other by means of strips of'mica. This insulation sometimes becomes broken during the'assembling of the commutator and the present device is designed to determine whether any break-in the insulation has occurred. No special attempt is made to locate the break, as every break in the insulation necessitates disassembling the commutator. i

In the drawing, 1 is a base on which is p of this invention, it being mounted a pin 2 having a collar 3 to center and support the commutator, which is shown to have an odd number of segments or bars 1, separated by strips 5 of insulation, usually mica. The core 6 is formed in the usual manner and is insulated from the segmentsby means of rings 7'and strips of mica (not shown), in any desired manner. The manner of insulating the segments from each other and from the core forms no part understood that in substantially all electric machines now in use or being built, the commutator segments must be insulated in some 'manner, and that the electric machine is defective when such insulation is broken.

A'small pedestal 8 carries a pin 9 on which the contact carrier 10 is mounted, provided with a central hole through which a commutator may project. On this carrier are secured the contact springs 12 and 13 in any desired manner, bolts 14 being shown, and these contact springs are united into two series by means of the wires 15 and 16, alternate springs belonging to one series, and the two series being connected to the posts 17 and 18 by the wires 19 and 20. Line wires 22 and 23 may connect these posts to the usual lighting mains of the factory. A current indicator 28 of any desired character, an electric lamp preferred,

contact spring 12 by means of a wire 25.-

The engagement of the contacts with the segments is but momentary and, as the carrier is lifted, the operator observes the inclicator to determine whether any current passes, for this occurs if there is a short circuit between segments. If'there is no indication of current, he turns the commutator the distance ofone segment and again engages the contact springs. Any arcing at any of the contacts indicates a short contact 13.

circuit between the segment engaged thereby and another segment or the core.

An additional contact 26 is mounted on the carrier 10, and preferably secured in position by a bolt it that also secures a This contact 26 engages the core, and so, if any of the contacts 12 or 24:

engages a segment which is not insulated 1 quickly tested. The proportions and sizes of the various parts of this device may all be changed by those skilled in the art without departing from the spirit of my invention as set forth in the following claims.

I claim:

1. In combination, a shaft upon which a commutator may be mounted, a contact carrier, a series of contacts adapted to engage alternate segments of the commutator, a conductor connecting the contacts in series and .to one pole of a current source, a second series of contacts adapted to engage, the remaining segments of the commutator, and a separate conductor connecting the second group of contacts in series and to the other pole of said current source.

2. In combination, a base and a shaft thereon upon which a commutator may be mounted, a contact carrier pivotally mounted on said base and having a central opening and adapted to be swung down over the commutator, a seriesof radial contacts mounted on the carrier and adapted to engage alternate segments of the wnunutator, a conductor connecting the contacts in series and one pole of a current source, a second series of radial contacts mounted on the carrier and adapted to engage the remaining segments of the commutator, and a separate conductor connecting the second series of contacts to the other pole of the current source.

3. In combination, a base and a shaft thereonupon which a commutator may be mounted, a contact carrierpivotally mounted on said base and having a central opening and adapted to be swung down over the commutator, a series of radial contacts mounted on the carrier and adapted to engage alternate segments of the commutator,a conductor connecting the contacts in series and one pole of a current source, a second series of radial contacts mounted on the carrier and adapted to engage the remaining segments of the commutator, a separate conductor connecting the second series of contacts to the other pole of the current source, and an addi tional contact connected to one of the conductors and adapted to engage the core of the commutator.

4:. In combination, a base and a shaft thereon upon which a commutator may be mounted, a contact carrier pivotally mounted on said base and having a central opening and adapted to be swung down over the commutator, a series of radial contacts mounted on the carrier and adapted to engage alternate segments of the commutator, a conductor connecting the contacts in series and one pole of a current source, a second series of radialcontacts mounted on the carrier and adapted to engage the remaining segments of the commutator, aseparate con ductor connecting the second series of contacts to the other pole of the current source, and an additional contact connected to one of the conductors and adapted to engage the core of the commutator, said contacts being evenly spaced and attached at their outer ends to the carrier andpointing toward a common center.

5. In combination, a support upon which a commutator may be rotatably mounted, a contact carrier and-two. series of contacts mounted on the carrier and each series adapted to engage alternate segments of the commutator, and electric conductors con.- necting the contacts into two series.

6. In combination, ashaft upon which a commutator may be mounted, a contact carrier, a series of contacts adapted to engage alternate segments of the commutator, a conductor connecting the contacts in series and to one pole of a current source, a current indicator connected into said conductor, a second series of contacts adapted to engage theremaining segments of the commutator, and a separate conductor connecting the remaining contacts in series and to the other pole of said current source.

7. In combination, a base and a shaft thereon upon which a commutator may be mounted, a contact carrier pivotally mounted on said base and having a central opening and adapted to be swung down over the commutator, a series of radial contacts mounted on the carrier and adapted to engage alternate segments of the commutator, a conductor connecting the contacts in series and one pole of a current source, a current indicator connected into said conductor, a second series of radial contacts mounted on the carrier and adapted to engage the remaining segments of the commutator, and a separate conductor connecting the second series of contacts to the other pole of the current source.

8. In combination, a base and a shaft thereon upon which a commutator may be mounted, a contactcarrier pivotally mounted on said base and having a central opening and adapted to be swung down over the commutator, a series of radial contacts mounted on the carrier and adapted to engage alternate segments of the commutator, a conductor connecting the contacts in series and one pole of a current source, a second series of radial contacts mounted on the carrier and adapted to engage the remaining segments of the commutator, a separate conductor connecting the second series of contacts to the other pole of the current source,

a current indicator connected into one of said 10 conductors, and an additional contact connected to one of the conductors and adapted to engage the core of the commutator, said contacts being evenly spaced and attached at their outer ends to the carrier and point- 15 ing toward a common center.

JASPER F. CULLIN. 

